Cyclic adenosine 3',5' -monophosphate (cAMP) and its binding proteins are involved in the regulation of the growth of mammary tumors in experimental animals. Whilst human breast cancers which possess estrogen receptor (ER) and progesterone receptor (PgR) activities are likely to be hormone responsive, many do not respond to endocrine therapy. In hormone-dependent rat mammary tumors the ratio of steroid receptors to cAMP binding proteins was found to better discriminate hormone dependent from independent tumors than steroid receptor alone. In this study we will investigate the relationship between cAMP proteins, ER and PgR in human breast cancers and clinical parameters including prognosis. Several molecular species as well as proteolytic fragments of cAMP binding proteins have been found in normal and neoplastic tissues. Thus, molecular species of cAMP binding proteins will be determined by utilizing the photo-affinity ligand, 8-azido-[32P]cAMP and immunoprecipitation using affinity purified antibodies to cAMP binding proteins. Utilizing immunocytochemical method intra-cellular distribution and nuclear compartmentalization of cAMP binding proteins will be also determined. Finally, in a cell-free system, the binding of cAMP binding proteins directly to DNA of normal vs cancer cells will be studied utilizing molecular biology techniques. The goal of this proposal is to provide us a fundamental growth regulatory mechanism of cAMP action in breast cancer.